Still smarting from a $13.5 million New Jersey verdict over its painkiller Vioxx — and a judge’s referral of the case to state prosecutors for possible criminal action — Merck & Co. got some welcome good news from a federal court.

U.S. District Judge Stanley Chesler in Newark, N.J., dismissed shareholder derivative suits against the company, finding the plaintiffs failed to comply with a federal court rule requiring shareholders to demand, prior to filing suit, that the board of directors take corrective action.